As Labour MP for Sunderland South, Gordon Bagier, who has died aged 87, specialised in the transport issues for which his experience as a railwayman had equipped him. He also served the home secretaries Roy Jenkins and James Callaghan as parliamentary private secretary, though attracted greater attention for his endorsement of the regime of the Greek colonels while a consultant to their PR company in Britain.

Born in Newcastle upon Tyne, Bagier went to the local Pendower secondary technical school, and then worked on the railways. During the second world war he was with the Royal Marines (1941-45), mainly on HMS Belfast (now moored on the Thames in London). After Arctic convoys to Russia and supporting the D-day landings, the ship went to the far East, where Bagier encountered scenes of extreme poverty, which sparked his interest in political involvement.

After returning to railway work, he was promoted to signals inspector (1950-64). Active in the National Union of Railwaymen (NUR), he eventually became president of its Yorkshire district council (1962-64). He was a councillor in Keighley (1956-60) and Sowerby Bridge (1962-65).

Having been selected for Sunderland South with NUR sponsorship, in 1964 he won the seat from its Conservative incumbent, Paul Williams. This helped to provide the narrow majority of Commons seats that enabled Harold Wilson to become prime minister.

Education was an early interest: in his maiden speech he supported the principle of comprehensive schools, and when he sought better funding for the north-east of England, he urged that it be provided with a technological university.

Jenkins appointed him his PPS in 1967, but that year's devaluation of sterling led to Jenkins exchanging posts with Callaghan as chancellor of the exchequer. Callaghan had been impressed by Bagier's advocacy of a gaming board with wide powers, and so asked him to stay on. Bagier's interest also brought him into contact with the PR man Maurice Fraser, then promoting the cause of casinos.

In April 1968, as Fraser's guest, Bagier was invited to visit Greece, which since the previous year had been run by a junta of colonels. He responded to complaints about human rights abuses and torture by claiming that the UK media were biased, giving a slanted picture of a scene he had observed for only a few days.

After denying reports that the Greek colonels had an MP-lobbyist on their payroll, he admitted having received £500 for serving as parliamentary consultant to the Fraser PR company, which had a £100,000 contract to improve their image abroad, but insisted that he had not seen himself as a lobbyist. The episode contributed to the eventual establishment of the Register of MPs' Interests.

In 1975 Bagier accepted an expenses-paid trip to apartheid South Africa, without seeking the permission of his chief whip. He became treasurer of the Inter-Parliamentary Union and officer of the parliamentary groups dealing with Japan, Morocco and Jordan.

An early advocate of coordinated transport, Bagier campaigned for funding of the Tyne and Wear Metro, which opened in 1980. He chaired the NUR group, assailed British Rail for its low wages, called for rail electrification and chided Margaret Thatcher for never using the railways. As chairman of the transport select committee (1985-87), his was the casting vote that recommended the Channel Tunnel should be rail-only, instead of the road link preferred by Thatcher and her transport secretary, Nicholas Ridley. He was unable, however, to stop their deregulation of the bus networks or the privatisation of the National Bus Company.

As a rightwinger, he naturally attracted leftwing opposition, particularly from Militant, whose Trotskyist members made a tremendous effort in the 1980s to penetrate and capture small constituency Labour parties. In June 1982 Bagier fought off the efforts of a local leftwinger to unseat him.

But in November 1984, when he was 60, he announced that he would not stand again. He was succeeded by Chris Mullin, the former editor of Tribune. A year after his term ended in 1987, Bagier was made deputy lieutenant of Tyne and Wear.

In 1949, he married Violet Sinclair. She survives him, as do their two daughters and two sons.